Rock drill



Oct. 14, 1941.

J. c. uR-rls ROCK DRILL Original Filed Feb. 14,

-1958 Y2 sheets-sheet 1 2 Shets-#Sheet J. `c. CURTIS Rocx DRILL original Filed Feb'. 414, 1938 Oct'. 1 4, 1941'.

Patented Oct. 14, 1941 ROCK DRILL John C. Curtis, VClaremont,\l\l. H., assigner to Sullivan Machinery Company, a corporation of Massachusetts Application February 14, 1938, Serial No. 196,356 Renewedhlovember 4, 1939 (Cl. Z55-45) 18 Claims.

This invention relates to rock drills, and 4more particularly, but not exclusively, to improvements in the feeding mechanism of a hammer rock drill of the mounted drifter type. l 5 l In hammer rock drills of the mounted drifter` type, it is a well known practice to effect drill feed relative to its guide shell, by 'meanzsnconrtrolled automatically by the vibratory actionwof the hammer motor resulting from the force of the jars imparted by the hammer piston due to the sudden reversal in the direction ofn piston movement, by jumping the dri ll step by step either forwardly or rearwardly alongl the shell guideways. In such automatic feeds it has usually been the practice to employ reversible ratchet and pawl or roller grip devices for controlling rotation of the feed screw so that the feed nut fixed to the hammer motor cylinder has a step by step movement along the feed screwfinthe desired direction, the ratchet or roller gripldevice permitting the feed screw to rotate freely in the feeding direction and holding the feed screw against rotation in the opposite direction.'Y The main objections to such automatic feeding devices are the relatively Icomplicated nature of the intermittent grip devices andthe relatively short life of the component parts thereof due Vto concentrated wear. The roller type""grip device has, incertain respects, advantages over thatof the ratchet and pawl device in that thedgree of screw rotation is not predetermined by spaced ratchet teeth since the rollers grip immediately whenever the screw tends to rotate in the reverse direction. Due, however, to the" above ldisadvantages, automatic feeding mechanisms'of'th above type have not met with complete success.

A primary object of the present invention` is to provide an improved vibration controlled feeding mechanism for a hammer rock drill whereby the disadvantages of previous devices, as above outlined, are substantially overcome in that com'- plication is avoided and a positive controlling action is attained. A further object is to provide in a drill feeding mechanism of'thelabovef chai"- acter an improved intermittent grip device embodying reversing means whereby feed may be eected in either of opposite directions in an improved manner. Still another object is toprovide an improved intermittent grip device whereby, due to its novel design, wear is reduced to a minimum. A still further object is to provide an improved intermittent grip device wherein the reaction member is free to rotate, thereby to reduce concentrated wear such as occurs when the another object is to provide an improved 4intermitt'ent.gripA device of the roller "type having an improved gripping arrangement for `the rollers and improved roller release means. Other objectsandadvantages of the invention will hereinafter more fully appear in the vcourse of the following vdescription and as more particularly pointed out in the appended claims.

In the accompanying drawings there are shown for `purposes of illustration two forinsfwhich the invention may assume in practice.

t In these drawings- Fig.'1 is a View in longitudinal vertical section, with parts in side elevation, of ahammer rock drill with which an illustrative embodiment of the'invention is associated.

Fig. `2 is an'enlarged, fragmentary, vplan View VoftheV improved automatic control means.

Fig. 3 is a View in longitudinal-vertical section taken substantially onY line 3 3 of Fig. 2.l

Fig. 4 isfa cross sectional view taken'sub'stantially on line 4 4 of Figs. land 3.' A Fig. 5 is a cross sectional view taken substantially Online 5 5 0f Figs. 1 andB.A

"taken substantially on line 9 9 of Fig.`8.

In bothillustrative embodiments of 'the invention, the` improved liee'dingfmeans is associated `with av hammer rock drill of the-mounted drifter type, although it will be evident 'that the 'improved vfeeding mechanism may be incorporated in rock drills of various other types. The rock vdrill is slidably mountedron the horizontal guide- ,motor cylinder has a front head 8 and a front chuck housing 9, the head and chuck housing being secured to the forward end. of the cylinder. The. hammer piston has a forwardly `projecting striking bar [0 guided in a bore Il formed in the front motor head and adapted to transmit 'impact blows to the shank cfa drill steel |'2', the

latterV being supported within a chuck bushing vI3 secured to a chuck sleeve I 4 rotatably mounted reaction member is relatively stationary. Still 55 within-the chuch housing 9. VThe motorcylindr lentially extending groove di.

has a rear head block l suitably s-ecured to the rear end of the cylinder, and arranged between this head block and the rear end of the cylinder is a combined rear cylinder head and valve box i6 and a valve box cover H, the parts l5 and l1 cooperating to provide a valve chamber in which is mounted an automatic fluid actuated fluid distributing valve i8 of a conventional design. The valve I8 is adapted to control the flow of pressure fluid through suitable ports and passages to the bore of the motor cylinder to effect reciprocation of the hammer piston, in the manner well known to those skilled in the art. As the particular structure of the rock drill per se does not enter into this invention, other than its particular manner of association therewith, further description thereof is herein considered unnecessary.

In both illustrative embodiments of the im'f.

proved feeding mechanism, the improved control means is associated with a rotatable feedscrew 20, the latter engaging a non-rotatable feed nut 2| secured within the bore of a depending lug 22 formed integral with the motor cylinder. This feed screw is journaled at its forward end within a bearing yoke 23 secured to the front end of the guide shell 2 and at its rear end within the casing of the control means in a manner to be later described.

In the illustrative embodiment of the inven- Y tion shown in Figs. 1 to 6 inclusive, the improved control means has a casing 213 secured by parallel ti-e bolts 25 and cooperating spacing sleeves 26 to the rear end of the guide shell 2 in the Inanner shown in Fig. 1. 2'! closed at its rearward side by a detachable cover plate 23 secured to the casing by the tie bolts 25, as shown in Fig. 3. By removing the nuts of the tie bolts, the cover plate can be readily detached from the casing, to obtain access to the internal mechanism. The feed screw 2D has a rearwardly extending shaft portion 29 extending within the casing bore, and this shaft portion has keyed thereto a cylindric member 39 having a smooth external peripheral surface 3|. cylindric member receives the axial thrust of the feed screw in opposite directions and is held against axial displacement with respect to the screw shaft by a holding nut 32 threaded on the rearward portion of the shaft, the nut, when tightened, clamping the cylindric member against a shoulder 33 on the screw. The cylindric member 3G has oppositely projecting bearing portions 31% journaled within alined bores 35 and' formed respectively inthe front end casing wall and :I:

the cover plate 28. The aiined bores 35, 3S are eccentric with respect to the casing bore 2'! and the shaft portion 2S of the screw extends eccentrically within the casing bore in the manner shown in Figs. 4 and 5. Mounted for free rotation within the bore 2i' of the casing 24 is areaction member in the form of a sleeve-like annulus 37 having a smooth internal peripheral surface 38. Arranged in the space 3S between the eccentrically disposed surfaces 3l and 33 are gripping rollers GQ of cylindric form each. having midway between its ends an annular circumfer- Also arranged in the space 39 Ais a spring al! of loop-bent form having projecting ends 'seated within the grooves il in the rollers, the ends 43 of the spring also engaging the surface 38 of the reacition annulus 37 in the manner shown in Fig. 4. This spring constantly urges the rollers lil toward frictional gripping engagement with the The casing 2li has a bore This n y of the projection.

surfaces 3l, 38. Surrounding the cylindric member 33 and arranged within the reaction annulus 3? is a sleeve-like shifter annulus 4 having its ends rotatably mounted within annular grooves formed in the front end casing wall and the cover member 28, as shown in Fig. 3. The member M is cut away at l5 at circumferentially spaced points, and the rollers Q3 are arranged within these cut away portions (see Fig. fr). The means for rotating the annulus "tl comprises a shaft d journaled within .a bore lll formed in the cover plate 28 (see Fig. 3). This shaft has an integral projection i3 extending within a slot [i9 formed in the annulus M. The cover plate 28 is preferably cut away at 59 to permit movement Secured to the shaft 46 is an operating lever El. When the annulus lill is rotated in a counter-clockwise direction, as viewed in Fig. 4, an end wall of the right hand cut away portion 65 engages the right hand roller lf3 and moves the latter against the pressure of the spring ft2 out of concurrent engagement with the peripheral surface 3i and the surface 3B of the reaction annulus 3l', while the left hand roller remains in engagement with both of these surfaces, and when the annulus iid has turned in a clockwise direction, the left hand roller is released from concurrent engagement with the surfaces `3| and 38 while the right hand roller s in engagement therewith. Thus by rotating the control annulus G the gripping rollers may be selectively rendered active.

In the embodiment of the invention shown in Figs. 7 to 9 inclusive, the control means has a casing E secured by the tie bolts and spacing sleeves 25, 2B to the rear end of the guide shell 2, Yand this casing has a bore 5S closed at its rear side by a detachable cover plate El, the cover plate and casing being held together by the tie bolts. In this construction, the feed screw 2f! has a, rearwardly extending sha-ft portion 58 projecting axially within the casing bore and journaled within alined bores respectively in the 'front casing wall and cover plate as shown in Fig. '7. Surroundingand preferably integral with the shaft portion 58 of the screw is a disc-like plate 59 arranged in the casing bore, and interposed between the front surface of the plate and the rear surface of the front casing wall is a ball thrust bearing 60 for receiving the endwise axial thrust of the screw in a forward direction. Also .arranged within the casing bore in an inclined position with respect to the plate 5g is a reaction member in the form of an annular plate El surrounding the screw shaft portion 53 in the manner shown in Fig. '7. This plate has a sleeve-like 'hub 62 rotatably mounted in a bore 63 in the Vcover plate, and the bore of the plate hub is rearwardly and outwardly tapered at S to permit the plate to rotate with respect to the casing as the shaft portion rotates. The shaft portion 58 at the rear of the plate 59 is formed with splineways 65, and splines 56 on the plates E! project withinthese splineways so that the plate rotates with the shaft. Interposed between the rear reaction surface of the plate Si and the front reaction surface of the cover plate is a ball thrust bearing Sl for receiving the `axial thrust of the screw in a rearward direction. Arranged between and engaging the inner adjacent surfaces of the plates 59 and 6| are gripping rollers E8 of Acylindric form, and these rollers are constantly urged toward gripping engagement with the plate surfaces by spring-pressed plungers 69. Arranged in the'casing bore between the plates 59 and Gl is an arcuate shifter member having `its, exterior surface tting the bore 56 of the casing and its inner surface curved to conform with the exterior shaft periphery. The shifter member 'Ill has end surf-aces Il engageable with the rollers for selectively moving the latter lagainst the pressure of the plunger springs out of concurrent engagement with the rear surface of the plate 59 and the front surface of the plate 6I. The means for moving the shifter member 'lll into its different roller releasing positions comprises a shaft 12 rotatably mounted in alined bores in the casing and cover plate and having an operating handle i3. This shaft has a projection k'Ill arranged to move in a slot 'l5 cut in the inner wall of the casing and projecting within a recess 1B in the shifter member. When the shaft 'l2 is rotated,

the projection 'M engages an end wall of therecess 76 to move theshifter membe'r in one direction or the other to bring a surface 'Il thereon into releasing engagement with a roller.

The general mode of operation ofthe improved automatic feeding mechanism is as follows: In both embodiments of the invention, when the hammer motor is running to effect percussive actuation of the drill steel l2, the reciprocatory movement of the hammer piston I causes, due to the sudden reversal in the direction of movement of the piston within the motor cylinder, a vibratory or recoil movement in a direction longitudinally of the hammer motor as is Well known by those Skilled in the art. Movement of the hammer motor in a direction opposite from the direction of feeding movement with respect to the shell guideways is checked automatically by the intermittent roller gripping device, the rollers slipp-ing automatically to permit free movement of the hammer motor in the feeding direction. In the form of the invention shown in Figs. 1 to 6 inclusive, when the shifter annulus 44 is in the position shown in Fig. 4 the feed screw is free to rotate in a clockwise direction as viewed in Fig. 4, thereby permitting the feed nut 2l to move vin a forward direction relative to the screw, the nut as it moves forwardly effecting rotation of the screw. Rearward movement of the feed nutv relative to the feed screw is checked automatically by the active roller @il frictionally engaging the surfaces 3| and 38, the roller as it wedges in between the surfaces causing movement of the reaction annulus 3l into frictional engagement with the walls of the casing bore 21, and as a result rotation of the feed screw in a counter-clockwise direction as viewed in Fig. 4 is prevented. It will thus be seen that as the hammer piston 'l of the hammer motor reciprocates within the cylinder bore to effect percussive actuations of the drill steel, the jars imparted by the hammer piston due to the sudden reversal in the direction of movement thereof cause the hammer motor to jump step by step in a forward direction along the shell guideways, thereby feeding the drill steel toward the work. When the operator manipulates the handle 5 l, the shifter annulus 44 may be rotated to render the left hand roller shown in Fig. 4 inoperative to effect locking and to permit the right hand roller to move under the pressure of the spring into gripping engagement with the surfaces 3l and 38. When the parts are in this reversed position the feed screw, as viewed in Fig. 4, is free to rotate in a counter-clockwise direction so that as the `hammer piston rapidly reciprocates within the motor cylinder to actuate percussively the drill steel, the feed nut is moved in a rearward direction with respect to thefeed screw due tothe jars set up by the hammer piston, Athe yactive roller releasing automatically to cally the feed screw against rotation in the opposite direction, i. e. the clockwise direction as viewed in Fig. 4. When the shifter annulus 44 is moved into its intermediate position, both friction rollers 40 are free to engage the surfaces 3| and.3r8, and.as a' result the feed screw is locked against rotation in both directions so that movement of the hammer motor along the shell guideways is prevented. The embodiment of the invention shown in Figs. '7 to 9 inclusive operates in the` same general manner as that above described, except, in this instance, the gripping rollers engage the relatively inclined surfaces of the plates 59 and 6l to lock the plates against rotation relative to the casing in one direction while permitting free rotation thereof in the opposite direction so that, with the arrangement as shown, movement of the drill along the shell guideways in a rearward direction is permitted while forward movement is automatically precluded. When the operator moves the shifter member l0 in its opposite position, the left hand roller shown in Fig. 8 is made ineffective while the right hand roller is free to move into gripping engagement with the plate surfaces, and as a result the direction in which the feed-screw is free to rotate is reversed so that the rock drill may be fed in a forward direction along the shell guide- Ways. When the shifter member 'lli is in its intermediate positionboth friction rollers are free to grip the plate surfacesto lock the feed screw against rotation in both directions. In both embodiments of the invention the member'on which the active roller reacts is adapted to rotate when the rollers are released so that the gripping rollers engage Vthe surface thereof at different points, the annulus 31 shown in Fig. 3 being freefloating while the member El shownin Fig. 7 is positively rotated whenever the feed screw is rotated.

As a result V`of this invention, it will be noted that by the provision of the improved intermittent grip device an improved automatic feeding means is provided fora hammer rock drill whererotation, all relatively complicated structure is l eliminated and increased life is obtained due to the avoidance of concentrated wear. It will further be noted that an improved intermittent grip device is provided wherein the reaction member for the gripping devices is mounted for free rotation so that when the gripping rollers are released the reaction member is free to rotate about its axis so that the rollers engage the gripping surface thereof at different points, thereby increasing the life ofthe parts by avoiding concentrated wear. It will still yfurther be evident that an improved automatically controlled drill feed is provided which is relatively simple and rugged in design, well adapted to withstand the severe conditions encountered in service. Other uses and advantages of the improved automatic feeding means will be clearly apparent to those skilled in the art. f

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure b-y Letters Patent is:

1. In Va rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston,

hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, res ectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, means normally operative to preclude material rotation oi said rotatable element in one direction while permitting free rotation thereof in the opposite direction including a control member rotatable with said rotatable element, a reaction member, gripping means operative to engage said members to lock the latter against rotation in one direction while permitting free relative rotation thereof in the opposite direction, and means for mounting said reaction member for free rotation so that the same may rotate into diierent positions when said gripping means is released, said reaction member presenting a circumferentially continucus surface surrounding its axis of rotation and engageable by said gripping means.

2. In a roel; drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston,

hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, respectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, means normally operative to preclude material rotation of said rotatfree rotation thereof in the opposite direction including a casing stationary with respect to said guide and having a bore, a member arranged within said casing bore and rotatable with said rotatable element, an annular peripherally continuous reaction memb-er arranged in said casing bore, gripping means automatically operative to engage said members to lock the latter against rotation relative to said casing in one direction while permitting free rotation thereof in the opposite direction relative to said casing, and means for mounting said reaction member Within said casing bore for free rotation relative to said casing so that the same may rotate into dilferent positions when said gripping means is released.

3. In. a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston, hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are prcducedduring running aesaesi 'of the motor, and means controlled by said alernating tendencies to movement forwardly and rearwardly forv effecting feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, respectively carried by said guide and said motor and mutually intereng-aged so that movement of said motor along said guide is precluded except upon rotaion of said rotatable element, means normally operative to preclude material rotation of said rotatable element in one direction, said rotationprecluding means including a member rotatable with saidrotatable element, a reaction member, and gripping means operative to engage said members to lock the same against rotation in one di ection while permitting free relative rotation thereof in the opposite direction, said reaction member mounted for free rotation so that the same may rotate into different positions when said gripping means is released, and means adjustable to render said rotation-precluding means wholly ineffective notwithstanding rotation of said rotatable element in said one direction.

ll. In a rock drilling mechanism, in combination,

a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer motor for movement therewith, and means for controlling rotation of said rotatable element for automatically holding the same against rotation one direction while permitting free rotation hereof in the opposite direction comprising a control member rotatable with said rotatable clement, a rotatable reaction member and a gripping element engageable with said members automatically to lock the same against relative rotation in one direction while permitting free relative rotation thereof in the opposite direction,

rotatable reaction member presenting a circumferentially continuous reaction surface for engagement by said gripping element, and means for mounting said rotatable reaction member for free rotation so that the same may automatically rotate freely into different positions when said grippingn element is released.

5. In a rock drilling mechanism, in combination, a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer motor for movement therewith, and means for controlling rotation of said rotatable element for automatically holding the same against rotation in one direction while permitting free rotation thereof in the opposite direction comprising a stationary member having a bore, a rotatable reaction member in the form of a continuous annulus and mounted in said bore, a member rotatable with said rotatable element and a. gripping element engageable with said last two mem bers Yfor automatically locking the same relative to said stationary member against relative rotation in one direction while permitting free relative rotation thereof in the opposite direction, and means for mounting said reaction member for free rotation so that the same may autoaasaeil matically rotate freelyv into different positions when said gripping element isreleased.

6.Y In a rock drilling mechanism, in combination, a hammer motor in which longitudinal vibrations occur during operation fthereof, and feeding means for s-aid hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable andthe other continuously held againstrotation, said element continuously held against rotation being carriedby said hammer motor for movement therewith, and means for controlling rotation of said rotatable element for automatically holding the same against rotation in one direction while permitting free rotation thereof in the opposite direction comprising a stationary member having a bore, a reaction circumferentially lcontinuous sleeve rotatably mounted in said bore, a cylindric member arranged eccentrically within said sleeve and rotatable with said rotatable element,`a gripping member engageable with the exterior surface of said cylindric member and the interior surface of said sleeve for holding said sleeve against rotation relative to said stationary member, and .means for mounting said reaction sleeve for free rotation with respect to said stationary member so that'the same may rotate into different'positions when said gripping member is released.

Av'7. In 'a rock drilling mechanism, in comb-ination, a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer motor for movement therewith, and means for controlling rotation of said rotatable element for automatically holding the same against rotation in one direction while permitting free rotation thereof in the opposite direction comprising a cylindric member xed to and rotatable with said rotatable element, a circumferentially continuous sleeve mounted eccentrically with and surrounding said cylindric member, a stationary member having a bore receiving said sleeve and cylindric member, and a roller gripping element engageable with the exterior surface of said cylindric member and the interior surface of said sleeve for precluding rotation thereof relative to each other and to said bore.

8. In a rock drilling mechanism, incombination, a hammer motor in which longitudinal vibrations occur during operation' thereof and feeding means for said hammer motor controlled automatically byv the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer motor for movement therewith, and means for controlling rotation of said rotatable element for automatically holding the same against rotation in one direction while permitting free rotation thereof in theopposite direction comprising a plate rotatable with' said rotatable element, arelatively inclined plate rotatable with said rotatable element, a stationary casing enclosing said plates and having surfaces on which said plates react, anda roller larranged. between said relatively inclined plates and engageable therewith for locking the same against rotation relative to said casing.

9.v In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston, hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardlyv along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwvardlyand rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, respectively carried by said guide and Said motor and mutually interengaged so that movement of said motor along said guide is precluded except uponrotatirr of said rotatable element, means normally operative to preclude material rotation of said rotatable element in one direction while permittingffree rotation thereof in the opposite direction including a member rotatable with said rotatable element, a relatively inclined reaction member connected to said rotatable element for rotation therewith, a casing secured to said guide and enclosing said members and having surfaces on which said members react, and a gripping element arrangedbetween said relatively inclined members and engageable therewith for locking the same against rotation relative to said casing in one direction.

10. Inl a rock drilling mechanism, in combination, a hammermotor in which longitudinal vibrations occur during operationv thereof, and feeding means for said hammer kmotor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer moto-r for movement therewith, and means for'controlling rotation` of said rotatable feeding element for automatically holding Vthe same against rotation in one direction while permitting free rotation thereof rinthe opposite direction comprising'a stationary member having an annular surface, a member -mounted forf'free rotation with respect to said stationary member and of a fixed circumferential dimension, a member Yrotatable With said rotatable feeding element, andmeans cooperating kwith said freely rotatablemember and said last mentioned member for effectingthe holding of said rotatable feeding element against rotation in one direction and releasable automatically to free said rotatable vfeeding element to permit free rotation of said rotatablefeeding element inthe opposite direction.

11. In a rock drilling mechanism, in combination, a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, saidelement continuously held Vagainst rotation being carried by said hammer motor for movement therewith, and -means for controlling rotation of said rotatable feeding element for automatically Vholding the same against rotation in one direction while `permitting free rotation thereof in the opposite. direction comprising a stationary member having a bore, an annulus continuous throughout its periphery mounted for free rotation in said bore, a member'arrangedfwithinsaid annulus and having an eccentrically located portion 'and rotatable with said rotatable 'feeding element, and l means cooperating with said annulus and said eccentrically arranged portion for effecting holding of said rotatable feeding element against rotation in one direction and releasable automatically to free said rotatable element to permit free rotation of said rotatable feeding element in the opposite direction, and means for mounting said annulus for free rotation with respect to said stationary member so that the same may rotate into different positions when said rotatable element is released.

l2. In a rock drilling mechanism, in combination, a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements, one of which is rotatable and the other continuously held against rotation, said element continuously held against rotation being carried by said hammer motor for movement therewith, and means for controlling rotation of said rotatable feeding element for automatically holding the same against rotation in one direction While permitting free rotation thereof in the opposite direction comprising a member rotatable with said rotatable` feeding element and having a plane surface, a member rotatable with said rotatable feeding element and having a cooperating plane surface inclined with respect to the axis of rotad tion of said rotatable feeding element, a stationary member relative to which said members are mounted for rotation and having surfaces on which said members react, and means arranged between said relatively inclined plane surfaces and engageable therewith for locking said rotatable members against rotation relative to said stationary member.

13. In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston, hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, respectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, means normally operative to preclude material rotation of said rotatable element in one direction while permitting free rotation thereof in the opposite direction including a control member rotatable with said rotatable element, a substantially rigid reaction member mounted for free rotation, and means operative to engage said members to lock the same against relative rotation in one direction while permitting free relative rotation thereof in the opposite direction, said reaction member being automatically freely rotatable into different positions when said locking means is released whereby concentrated wear of said reaction member is reduced to a minimum.

14. In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said roel: drill having a motor of the reciprocating piston hammer type in which alternating tendencies to longitudinal-movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said4 alternating tendencies to movement forwardly and rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements of which one is rotatably mounted, respectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, means normally operative to preclude material rotation of said rotatable element in opposite directions, said rotation-precluding means including a member rotatable with said rotatable element, a reaction member and gripping devices one operative to lock said members against rotation in one direction and another operative to lock said members against rotation in the opposite direction, said reaction member mounted for free rotation so that the same may rotate into different positions when one of said gripping devices is released, and adjustable means for releasing either one of said gripping devices.

l5. In a rock drilling mechanism, in combination, a hammer motor in which longitudinal vibrations occur during operation thereof, and feeding means for said hammer motor controlled automatically by the vibratory action thereof comprising cooperating feeding elements one of which is rotatable and the other continuously held against rotation, means for controlling rotation of said rotatable element for automatically holding the same against rotation in one direction while permitting free rotation thereof in the opposite direction comprising a reactive member having a bore whose surrounding surface is circumferentially continuous and which surface constitutes a reactive surface, a cylinder member arranged eccentrically within said bore and rotatable with said rotatable element, gripping means engageable with said cylinder m- .iber and said reactive member for holding said members against rotation in one direction, means for mounting said reactive member for rotation so that the same may rotate into different positions when said gripping means is disengaged from concurrent engagement with said cylinder member and said reactive member, and adjustable means for releasing said gripping means from concurrent engagement with said members.

16. In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston, hammer typeI in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of said motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for effecting feed of said rocl: drill in either of opposite directions along said guide comprising cooperating mutually interengaged elements, one of which is rotatable and the other continuously held against rotation, and means for selectively controlling rotation of said rotatable element in either of opposite directions including a member rotatable with said rotatable element, a reaction member and alternately operable, oppositely acting gripping elements selectively engageable with said members for automatically locking said members against relative rotation in either direction while permitting free relative rotation thereof in the opposite direction, said reaction member mounted for free rotation so that when said gripping elements are either of them released said reaction member may automatically rotate freely into different positions, and means for rendering one of said gripping elements wholly ineffective.

17. In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston, hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for electing feed of said rock drill along said guide comprising cooperating elements, of which one is rotatably mounted, respectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, means normally operative to preclude material rotation of said rotatable element in one direction while permitting free rotation thereof in the opposite direction including a control member rotatable with said rotatable element, a reaction member having a gripping surface, gripping means operative to engage said members to lock the latter against rotation in one direction while permitting rotation thereof in the opposite direction, and means for mounting said reaction member for rotation so that the same may rotate when said gripping means is released into different positions for coaction with said gripping means at different points upon the gripping surface of said reaction member, said reaction member having its gripping surface continuous throughout a full 360 surrounding its axis of rotation.

18. In a rock drilling mechanism, the combination of a rock drill, a guide therefor, said rock drill having a motor of the reciprocating piston hammer type in which alternating tendencies to longitudinal movement forwardly and rearwardly along said guide are produced during running of the motor, and means controlled by said alternating tendencies to movement forwardly and rearwardly for effecting feed of said rock drill along said guide comprising cooperating elements, one of which is rotatably mounted, respectively carried by said guide and said motor and mutually interengaged so that movement of said motor along said guide is precluded except upon rotation of said rotatable element, and means for precluding material rotation of said rotatable element in one direction and permitting free rotation thereof in the opposite direction including a control member rotatable with said rotatable element, a oircumferentially continuous reaction member, and gripping means each operative to engage said members to lock the latter against rotation in one direction while permitting the rotation thereof in the opposite direction, said reaction member having a mounting supporting the same for rotation when said rotatable element is freely rotatable in either direction and against which said reaction member is pressed by the action of said gripping means when said members are locked against rotation.

JOHN C. CURTIS.

CERTIFICATE 0E CORRECTION. Patent No. 2,258,951. october It, 19in.

JOHN C. CURTIS.

It is hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page li, first Column, line S9, olaim2, after "annular" and beforeperipherally insert a Comma; page 5, first Column, line i8, claim 6, strike out "circumferentially continuous" and insert the same in line 17, same Claim, before "reaotion"; and second column, line 11.6, Claim lO, strike out "a"; line 50, same claim, strike out "the", and for the claims now numbered lp, 5, 6, T, 8, 9, 1o, 1I, 12, 15, It, 15ans 16 read 5, 6, 7, 8,9, lo, 11, 12, 15, 1R, 15, 16 and ll. respectively; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the oase in the Patent Office.

Signed and sealed this 10th day of February, A. D. 19ML Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

